300/4v2: 4 Ch. Class A/B Full-Range Amplifier, 300 W

SKU # 98083

300/4v2

If you prefer a traditional Class A/B design taken to its highest possible level, the 300/4v2 is your amplifier, thanks to its outstanding fidelity, reliability and well-designed feature set.

This classic amplifier features JL Audio's unique, and patented, Absolute Symmetry Class A/B circuit and our R.I.P.S. power supply design for full power delivery (75 W x 4) over a wide range of load impedances and vehicle voltages.

This amplifier features a brushed aluminum finish with black powder-coated cast alloy heat sink and end caps.

Rated Continuous (RMS) Power @ 14.4 V

@ 4 Ω

75 W RMS x 4

@ 3 Ω

75 W RMS x 4

@ 2 Ω

75 W RMS x 4

@ 1.5 Ω

75 W RMS x 4

Bridged @ 8 Ω

150 W RMS x 2

Bridged @ 4 Ω

150 W RMS x 2

Rated Continuous (RMS) Power @ 12.5 V

@ 4 Ω

75 W RMS x 4

@ 3 Ω

75 W RMS x 4

@ 2 Ω

75 W RMS x 4

@ 1.5 Ω

75 W RMS x 4

Bridged @ 8 Ω

150 W RMS x 2

Bridged @ 4 Ω

150 W RMS x 2

General Specifications

Frequency Response

5 Hz - 30 kHz (+0, -1dB)

S/N Ratio, referred to highest rated power

>108.5 dB (A-weighted, 20 Hz - 20 kHz noise bandwidth)

S/N Ratio, referred to 1 W

>89.5 dB (A-weighted, 20 Hz - 20 kHz noise bandwidth)

Damping Factor @ 4 Ω

>300 / 50 Hz

THD+N @ Rated Power

<0.03% @ 4 Ω per Ch.

Input Voltage Range @ RCA Inputs

200 mV - 8 V RMS

Min.Copper Power / Ground Wire Gauge

4 AWG wire

Fuse Rating

40 A (AFS, AGU or MaxiFuse™)

Signal Processing

Filter Mode(s)

Low-Pass or High-Pass

Filter Slope(s)

12/24 dB/octave

Filter Frequency Range

50 Hz - 5 kHz

Detented, Calibrated Filter Freq. Potentiometers

Yes

Filter Defeat Function

Yes

Remote Level Control

No

Remote Level Modes

N/A

Channel Input Mode Switch

Yes (2/4 ch.)

Pass-Through Preamp Output

None

Source Channel Selection for PreOuts

N/A

Physical Specifications

Height (H)

2.36 in / 60 mm

Width (W)

13.40 in / 340 mm

Depth (D)

9.25 in / 235 mm

R.I.P.S. – Regulated, Intelligent Power Supply

Summary:The remarkable R.I.P.S. System ensures consistent power delivery over a wide range of battery voltages and load impedances.

Detailed Information:R.I.P.S. stands for "Regulated, Intelligent Power Supply" and is a central feature of JL Audio's 'Slash' and HD amplifiers.

"Regulated" means that the power supply adjusts its operation so as to maintain the amplifier's rated power output and low distortion operation over a wide range of vehicle voltages (11V-14.5 V). This contrasts with conventional, "unregulated" power supplies, which allow rail voltages to sag in direct proportion to drops in the supply voltage. This can result in significant power losses when battery voltage decreases, even if those voltage dips are short in duration. This manifests itself audibly as increased distortion. With a JL Audio R.I.P.S.-equipped amplifier, the rail voltage and clean power output remain completely stable in real-world systems, resulting in superior fidelity and stability.

The "Intelligent" portion of the R.I.P.S. System is a circuit that actually monitors output current to optimize the amplifier's output power over a wide range of load impedances (1.5 ohm to 4 ohm per channel).

Conventional amplifiers are designed to produce optimum power at a particular impedance (2 ohms, for example). When asked to run above that impedance (say, 4 ohms), these amplifiers lose power (half their power from 2 ohms to 4 ohms). This will not happen with a JL Audio HD or 'Slash' amplifier because the R.I.P.S. System detects the actual impedance being driven and adjusts the amplifier's operation to deliver optimum output. The entire process is seamless, automatic, and results in incredible dynamics for satellite channels and consistent power output for a wide range of subwoofer configurations. It also takes into account the real impedance of the system, rather than relying on often inaccurate assumptions based on a speaker's rated impedance.

The bottom line: Optimum power, at any impedance between 1.5 ohm and 4 ohm per channel, at any vehicle voltage between 11V and 14.5V.

Advanced Rollback Protection

Detailed Information:Should a JL Audio amplifier equipped with Advanced Rollback Protection reach an unsafe operating temperature, a special circuit rolls back peak power output, without changing gain, until the amplifier cools down to a safe operating temperature. The condition is generally indicated by a red “Thermal” or “Status” LED state. On VXI amplifiers, the LED ring will flash red. Once the amplifier cools down, the circuit restores full peak power output and the indicator reverts to its normal state. The operation of Advanced Rollback Protection is inaudible in most cases, but it ensures that your music keeps on playing, even under the most demanding conditions.

Absolute Symmetry Class A/B Circuitry (U.S. Patent #6,294,959)

Detailed Information:At a time when many manufacturers are passing off crude Class B amplifiers as Class A/B designs, JL Audio engineers focused on taking the already excellent fidelity of true Class A/B designs to an even higher level.

Until now, the accepted approach for building high-fidelity Class A/B amplifiers has been to utilize "Complementary" output stages, which use different types of transistors to "push" the speaker and "pull' the speaker. The problem with this approach is that true "mirror-image" transistors are impossible to create, leading to asymmetrical clipping behavior. The negative side of the waveform runs out of voltage (clips) before the positive side does.

Another approach is to use the same type of transistor for both push and pull but without buffering from the load impedance. This solves the problem of asymmetrical clipping, but leads to significant increases in distortion as load impedance drops, making this design less desirable (in our opinion) than the "complementary" approach.

JL Audio's Absolute Symmetry™ amplifier design solves the entire issue once and for all with a revolutionary Class A/B circuit that employs identical N-Channel MOSFET transistors for push and pull with true buffering from the load impedance. This is accomplished via a patented circuit that reverses the operation of one of the transistors in each pair to achieve absolute power symmetry and extremely low distortion over a wide range of load impedances.

Some might call this sort of thing "a tad obsessive", or even "unnecessary". Our position is "If you can't make it better, why bother at all?"

RealSink™

Detailed Information:Most car audio amplifiers rely on big lumps of metal that do a good job of storing heat, but not such a great job of getting rid of it. RealSink™-equipped JL Audio amplifiers feature real cast-alloy heat sinks with vertically-oriented fins. This design is far more effective than the lump-of-metal approach, utilizing the physics of convection and radiation to more effectively exchange heat with the surrounding air. The design of these heat sinks was refined through extensive finite-element analysis, resulting in amplifiers that keep their cool under the most demanding conditions.

JL Audio Amplifiers and Electronics are warrantied against defects in materials and workmanship for Two (2) Years from purchase date. The Mobile Audio Amplifier warranty can be expanded to a total of Three (3) Years from the date of purchase with the accompanying purchase of a qualifying JL Audio Amplifier Power Connection System and with installation by a JL Audio Authorized Retailer. JL Audio will, at its discretion, repair or replace any products that exhibit defects in materials and/or workmanship during the warranty period.

Please hold on to your sales receipt! All warranty service requires original sales receipt documentation. The warranty only applies to the original purchaser from an authorized retailer. Note: Products purchased from unauthorized dealers are not covered under warranty.

Warranty Limitations

The following is not covered under JL Audio's warranty program:1. Product with defaced, altered or removed serial numbers (no valid, legible serial number = no warranty).2. Product owned by anyone other than the original purchaser from an authorized JL Audio dealer. (The warranty is not transferable and will not apply to products purchased from unauthorized dealers.)3. Product that has been physically abused (run over by a car or beat with a hammer, for example).4. Product that has not been installed according to the instructions in the owner's manual5. Product in which repair and/or modification has been attempted by unauthorized parties6. Product damaged cosmetically due to improper handling or normal wear and tear7. Product damaged in an accident, due to criminal activity (attempted theft, gunshot damage, etc.) or by 'acts of God' (flooding, lightning, locusts, etc.)8. Custom finishes or other cosmetic treatments applied to products. (JL Audio will not be responsible for restoring or maintaining any custom finishes)9. Installation and shipping costs associated with removing, re-installing or shipping the product to JL Audio for warranty serviceAsk your dealer for details on warranty limitations.

If you need Service on your JL Audio Product:All warranty returns should be sent to JL AUDIO freight prepaid through an authorized JL AUDIO dealer and must be accompanied by proof of purchase (a copy of the original sales receipt.) Direct returns from consumers or non-authorized dealers will be refused unless specifically authorized by JL AUDIO with a valid return authorization number. Warranty expiration on products returned without proof of purchase will be determined from the manufacturing date code. Coverage may be invalidated as this date is previous to purchase date. Return only defective components. Non-defective items received will be returned freight-collect. Customer is responsible for shipping charges and insurance in sending the product to JL AUDIO. Freight damage on returns is not covered under warranty. Always include proof of purchase (sales receipt).

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"The sheer precision with which the thing is put together reminded me powerfully of the function-breeding-form thing that so much professional equipment seems to exhibit but the sound was the thing that impressed me most."

"Unlike most amplifiers which seem to change a little in sonic character as they are driven harder and harder, the deeply cunning power supply technology in this amplifier's guts that enable it to cope with all the oddity of real world battery voltage fluctuations, also seems to function to feed the actual amplifier circuits with an even amount of oomph throughout. Thus as you wick it up, it just gets louder and doesn't acquire any toughness or hardness."

"...this is still a true audiophile's delight and yet clever enough to cope with real world signal inputs and real world crap battery voltages."

"At the end of the day, all of this technology is of no use if the amp doesn't sound good, but there's no need to worry-it does. The staging is nice and wide with good imaging. The sound is full and avoids losing any detail. Very nice."

"The heavy duty aluminium heat sinks not only look good, but are efficient as well."

"What (R.I.P.S.) means in practice is that whatever the voltage supplied, the amp will always deliver the rated power."

– InCars (UK)

"The adaptive power supply really scores some extra points where it matters-driving speakers."

"Think of it as one of those high-current amps that has enough sense to know when it's not driving a low impedance load. The amp uses the higher rail voltages to increase current flow and, therefore, power into higher impedances."

"...the 300/4 has, by far, the coolest crossover in the automotive amplifier industry."